import uuid

def generate_uuid():
    """
    生成UUID（通用唯一识别码）
    
    Returns:
        str: UUID字符串，格式为：xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
    """
    return str(uuid.uuid4())


def generate_uuid_without_hyphen():
    """
    生成不带连字符的UUID（通用唯一识别码）
    
    Returns:
        str: 不带连字符的UUID字符串，格式为：xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
    """
    return str(uuid.uuid4().hex)
